Prince Giedroyc in Tver. Giedroyć (Lithuanian: Giedraitis; Russian and Belarusian: Гедройц; French: Guedroitz) is a Polish surname, originating from theGiedraitis family of the Grand Duchy of Lithuania.The Second and Third Editions of the Lithuanian Chronicle relate that Giedrius (Palemonids), a brother of Grand Duke Traidenis of Lithuania (late 13th century), built a castle, named itGiedraičiai, and adopted the title Prince of Giedraičiai. A document issued by Grand DukeVytautas of Lithuania in the period 1399-1429 settled a dispute between the Bishop of Vilnius and the Princes of Giedraičiai. Numerous members of the family were recorded in the 15th and 16th centuries, and thereafter, with the title Prince.

The two lines of the family for which coherent genealogies are available (the family's "central core") descend from (i) Prince Aleksander (late 15th century) and (ii) Prince Bartłomiej (died in 1524).The 1569 Act of Union inaugurating thePolish-Lithuanian Royal Commonwealthconfirmed that, as previously in the Grand Duchy of Lithuania, Lithuanian families of dynastic origin remained entitled to use the title Prince. Many subsequent Giedroyć family members, both of the Line of Aleksander and of the Line of Bartłomiej, were recorded with the title Prince – including several (of both Lines) whose right to the title was individually confirmed under Imperial Russian legislation of 1832. Other members did not seek such specific confirmation under the Russian Empire, but relied on confirmation of their noble status and princely origins under Russian legislation of 1801/3. The Imperial Russian heraldic authority classified these as "of the Princes". Under the usage of the Grand Duchy of Lithuania, as confirmed by the 1569 Act of Union, princely origins in themselves establish princely status.